Processes for the milling of polyols, such as sucrose, are known in the art. Milling is often desirable to reduce the size of crystalline particles of polyol, e.g., sucrose particles, and facilitate handling or storage of the polyol and/or mixing of the polyol with other components.
Processes for co-milling of polyols in the presence of additional components, e.g., starch or flour, is also known. For example, U.S. Pat. No. 3,694,230 to Cooke describes a co-milling process for making culinary mixes. Specifically, Cooke describes a process of co-milling flour and sugar together to make a primary ingredient for a cake mix. The sugar and flour are co-milled together prior to mixing with additional baking materials in order to make a more uniform mixture, resulting in easier preparation of the cake and a superior baked product.
Additionally, processes for milling sucrose to make smaller, finer particles, i.e., powdered sugar, are well known. It has been found that co-milling of sucrose with starch, a complex sugar, results in a superior powdered product. The starch acts as an anti-caking agent and causes the final powdered product to be more uniform in consistency, whereby the particulate size distribution is relatively constant, and the powdered product flows easily and smoothly without clumping.
In many conventional processes for forming co-milled polyols, the components which are co-milled are generally compatible with one another and are suitable for human consumption. However, polyols such as sucrose are often used as reactants and/or precursors for other useful products, one example of which is polyol fatty acid polyesters. Polyol fatty acid polyesters are useful as low calorie fats in various food products. Polyol and fatty acid lower alkyl esters are reacted in the presence of catalysts, to produce polyol fatty acid polyesters. However, polyols are typically hydrophilic while fatty acid lower alkyl esters are typically hydrophobic, whereby it may often prove difficult to form mixtures of the polyol and fatty acid lower alkyl ester in a solvent free transesterfication reaction. In order to achieve the desired transesterfication of the polyol, it is often necessary to bring the polyol and the fatty acid ester into the same phase. Alkali metal fatty acid soaps are conventional emulsifiers for transesterfication reactions of polyols using fatty acid lower alkyl esters, although other emulsifiers have been used to help solubilize the polyol in the lower alkyl esters.
There is a continuing necessity to improve processes for the manufacture of polyol fatty acid polyesters, including, inter alia, to provide a superior polyol feed stream for use in the transesterfication reaction of the polyol.